Gold Mickey Mouse Platy Dying?

[chudze]

 Hi, I have a 48 gallon tank and I just did a water test ammonia 0,nitrite 0 nitrate 10 high ph 8.0 my Dalmatian molly just died, and my Platy looks next. I just did a 50% water change and used api stress coat.  he still occasionally swims a little but lays on his side..  I don't know of what is wrong.  he looks skinny and has been hiding for a couple of days minus today.  Someone please help

 

[AshleyNZ]

Could be parasites/worms? 

 

[nic1]

I don't think your tank water is stable. Going through your old posts you stated that you have had platys going on 6 weeks which is when you got the tank.
At this stage the water parameters can swing and spike at any moment, a tank won't become stable in my opinion for at least 6 months, but before this time you need to keep stocking levels low so there isn't a major ammonia build up from food and waste. You also mention that there are 30 fish? Please correct me of I'm wrong....
At this point I would do a 30% water change every other day, even though your tests all suggest a cycles tank your fishes symptoms suggest other wise.
Let me know if any info I've gathered from your old post is incorrect, I'm just gathering info as you didn't mention when the tank was set up etc.
Thanks

 

[chudze]

 I do a 50% water change every other day.  I have 33 fish. I check the water parameters daily. no ammonia has been seen, and no nitrites. I do have nitrates present.  I do use a bubble wand daily, and the house that is a bubbler. I think there was a fish that was sick or had some parasite  and it spread. I'm just not sure. everyone this morning seems fine for now.